If what the professor is doing is legal in your country, and he is unwilling to accommodate your request, you should petition the institutional hierarchy, dean, president, or such for a change in policy. If you have a student governance committee/senate/parliament, you could approach them to approach the university to change the policy to use student ID's. In the U.S., published student IDs should cannot be the students federal ID number, aka social security number, nor a portion of that number. This requires a structural change to the computerized student records system and may take years to effect. In the interim, a system of nick names could be devised so that only YOU and your prof knows the whose nickname is whose. Also, most electronic databases have a record number assigned to each record, i.e. each student has a different record number, somewhat akin to a line number in a paper and pencil grade book. The prof could display that record number instead of a name. Maybe not the best solution, but probably the easiest to effect in the short term. He only needs to communicate students' record numbers to each student privately. Be mindful that, whatever the alias system is used, the ordering of the names on the posted list should not be in the real name alphabetical order. If your name is Aaron Aardvaark, or Zybignu Zzypata, most can detect who is first or last on the list. Beyond the university, you can petition your local senator or MP, as the case may be for a national or state law. That, again could take years.